It is known that some benzoxazine type compounds show herbicidal activity. They are described in U.S. Pat. No. 4,734,124, 4,761,174, 5,084,084 or 5,281,571, European Patent publication No. 0170191 or German Patent publication No. 3927438. Certain fused tricyclic compounds with herbicidal activity were described in European Patent publication No. 406993.
However, it is not known that benzoxazine type compounds with a functional group introduced at position 5 followed by cyclization afford fused tricyclic compounds which exhibit herbicidal activity.
This invention delineates a method for the control of undesired vegetation in a plantation crop by the application to the locus of the crop an effective amount of a compound described herein. The herbicidal compounds of the present invention are described by the following formula (I) or its salt: 
wherein Q is a heterocycle selected from the group consisting of Q1 to Q24: 
wherein R1 is hydrogen, alkyl, haloalkyl, alkenyl, alkynyl, amino, alkoxyalkyl, acetyl, alkoxycarbonylamino, alkylcarbonylamino or alkoxycarbonyl;
R2 is alkyl, haloalkyl, alkoxy, haloalkoxy or unsubstituted or substituted phenyl;
R3 is hydrogen, halogen, nitro, amino, alkylamino, haloalkylamino, cyano or amide;
R4 and R5 are independently oxygen, sulfur or imino;
Q6, Q7, Q10, Q16 or Q17 may be unsaturated containing one or two double bonds in the 6-membered ring;
Y is hydrogen or halogen;
xe2x80x94Lxe2x80x94Xxe2x80x94 is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94 xe2x80x94CR6R7xe2x80x94, xe2x80x94CR6R7xe2x80x94Oxe2x80x94, xe2x80x94Oxe2x80x94CR6R7xe2x80x94, xe2x80x94CR6R7xe2x80x94Sxe2x80x94, Sxe2x80x94CR6R7xe2x80x94, xe2x80x94CR6R7xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)xe2x80x94CR6R7, xe2x80x94CR6R7xe2x80x94S(O)2xe2x80x94, xe2x80x94S(O)2xe2x80x94CR6R7xe2x80x94, xe2x80x94CR6R7xe2x80x94CR6R7xe2x80x94, xe2x80x94CR6xe2x95x90CRxe2x80x94, xe2x80x94NR6xe2x80x94, xe2x80x94CR6xe2x95x90Nxe2x80x94, xe2x80x94Nxe2x95x90CR6xe2x80x94, xe2x80x94Nxe2x95x90Nxe2x80x94, xe2x80x94CR6R7xe2x80x94NR6xe2x80x94 or xe2x80x94NR6xe2x80x94CR6R7xe2x80x94;
A is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94S(O)xe2x80x94, S(O)2, xe2x80x94NHxe2x80x94, xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94C(NH)xe2x80x94 or xe2x80x94CR6R7xe2x80x94;
Axe2x80x2 is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94S(O)xe2x80x94, S(O)2, xe2x80x94NHxe2x80x94, xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94C(NH)xe2x80x94 or xe2x80x94CR10R11xe2x80x94;
n is an integer of 0 to 2;
m is an integer of 0 to 2;
B is N, CH, C, or N+
E is a bond, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, xe2x80x94NHxe2x80x94, xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94C(NH)xe2x80x94, xe2x80x94CR12R13xe2x80x94, xe2x80x94CR12R13xe2x80x94CR12R13xe2x80x94, xe2x80x94CR12xe2x95x90CR13xe2x80x94, xe2x95x90CR12xe2x80x94 or xe2x80x94NR12xe2x80x94;
D is xe2x80x94NRxe2x80x94, xe2x80x94Nxe2x95x90CR14xe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, xe2x80x94CR14R15xe2x80x94 or xe2x80x94CR14xe2x95x90CR15xe2x80x94;
R6, R7, R8, R9, R10, R11, R12, R13, R14 and R15 are independently hydrogen, halogen, hydroxy, cyano, nitro, amino, alkyl, alkenyl, alkynyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, alkoxy, haloalkoxy, aryloxy, heteroaryloxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, amninocarbonylamino, alkylaminocarbonylamino, arylaminocarbonylamino, alkoxyalkyl, alkylthioalkyl, alkoxycarbonylalkyl, cycloalkoxycarbonylalkyl, alkylcarbonyloxyalkyl, alkylcarbonylaminoalkyl, alkoxyalkylcarbonylalkyl, heterocycloalkyl, alkylsulfonyl, arylsulfonyl, alkenylcarbonyl, alkynylcarbonyl, cycloalkylcarbonyl, heteroarylcarbonyl, alkylthiocarbonyl, cycloalkyloxycarbonyl, arylthio-carbonyl, aryl-thiocarbonyl, heteroaryloxycarbonyl, aminocarbonyl, alkylaminocarbonyl, arylaminocarbonyl, heteroarylaminocarbonyl, alkoxycarbonylcarbonyl or arylcarbonylcarbonyl where any of these groups may be substituted with at least one substituent selected from the group consisting of halogen, cyano, nitro, amino, dialkylamino, hydroxyl, carboxyl, alkyl, alkenyl, alkynyl, cycloalkyl, alkylcarbonyl, alkylcarbonyloxy, alkoxy, alkoxycarbonyl, alkylthio, alkylthiocarbonyl, alkoxythiocarbonyl alkylaminocarbonyl, arylaminocarbonyl, alkylsulfonyl, alkenyloxycarbonyl, alkynyloxycarbonyl, aryl, arylcarbonyl, aryloxy, aryloxycarbonyl, arylthio, heteroaryl, heteroaryloxycarbonyl and methylenedioxy, wherein the alkyl moiety or aryl moiety may be substituted with at least one substituent selected from the group consisting of halogen, cyano, nitro, alkyl, alkoxy, haloalkyl, haloalkoxy, alkoxycarbonyl, cycloalkyl, aryl and heterocycloalkyl;
R is hydrogen, alkyl alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, alkoxyalkyl, alkoxyalkoxyalkyl, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, alkoxycarbonylalkyl, alkoxyalkoxycarbonylalkyl, cycloalkoxycarbonylalkyl, aralkyl, heteroaralkyl, aryloxyalkyl or heteroaryloxyalkyl where any of these groups may be substituted with at least one substituent selected from the group consisting of halogen, cyano, nitro, amino, carboxyl, alkylthioalkyl, hydroxyalkyl, CON(R16)R17 and COON(R16)R17;
R16 and R17 are independently hydrogen, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxyalkyl, alkylthioalkyl, alkoxycarbonylalkyl, cycloalkoxycarbonylalkyl, alkylcarbonyloxyalkyl, alkylcarbonylaminoalkyl, alkoxyalkylcarbonylalkyl, phenyl or benzyl where any of these groups may be substituted with at least one substituent selected from the group consisting of halogen, cyano, carboxyl, hydroxy, nitro and amino.